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An “object” clause is not necessarily a promise, says Federal Court of Appeal

April 17, 2012

It used to be common practice to include an “object clause” in a patent specification to clearly set out an over-arching objective of the invention. Many granted patents have multiple object clauses, setting out a number of goals for the invention. This practice died away as patent drafters came to realize that courts may interpret the object clause as a specific promise that limits the scope of the patented invention.

In a judgment last week, the Federal Court of Appeal upheld an earlier decision of Rennie J. in which he declined to interpret an object clause as a “promise” of utility: Mylan Pharmaceuticals ULC v. Astrazeneca Canada, Inc. et al. The decision involved Canadian Patent no. 1,337,420 for the compound anastrozole. Anastrozole is used to inhibit the enzyme aromatase and is used in treatment of forms of breast cancer.

Inventors are not required to promise that an invention realizes any particular advantages (leaving aside the specific issues with selection patents), but if they choose to make a promise in a patent application that their invention achieves a specific result, then that promise must be met (and demonstrated or soundly predicted, with sufficient disclosure, as of the filing date of the application). The recent Eurocopter case is one good example.

In this case, the patent application included the following object clause:

A variety of compounds possessing aromatase inhibitory activity is known, of which the most important clinically is aminogluthethimide [AG]. [AG], however, has the drawback that it affects other aspects of steroid metabolism, with the consequence that its use is often associated with undesirable side-effects. It is a particular object of the present invention to provide aromatase inhibitory compounds with fewer undesirable side effects than [AG]. (emphasis added)

Mylan argued that this last sentence should be construed as an explicit promise of utility. Even though the compound anastrozole actually achieves these advantages, Mylan argued that the promise of the patent was not fulfilled through sufficient disclosure. The lack of demonstrated utility satisfying this promise is fatal to the patent.

The Federal Court of Appeal agreed with Rennie J. that this sentence is not a promise. It is aspirational; it states a forward-looking aim of the patent. It states that the goal of the inventors at the time was to realize a compound with fewer undesirable side effects, without promising that they actually succeeded, or that the compound they were claiming as inventive was a solution.

Patentees can take some comfort in knowing that not every object clause in an existing patent creates a fatal flaw. Nonetheless, the fact that AstraZeneca nearly lost their patent for an effective and novel compound based on the presence of this otherwise innocuous sentence is another warning to patent drafters to avoid any language that might be read as a promise.